Abstract    INTRODUCTION: Diabetes control is one of the main conflict issues in diabetes management. Scientists, recently, recommend [increasing low glycemic index (LGI) foods in dietary regimen. The effects of cooked lentil as a low glycemic index food on serum blood glucose and lipid profile among type 2 diabetic patients has been investigated in this study.    METHODS: In a randomized cross-over clinical trial which was performed on 30 patients with type II diabetes mellitus, subjects were randomly divided into 2 groups. Group A followed the normal diet and Group B followed normal diet with 50gm cooked lentil and 6gm canula oil substitute of 30gm bread and 20gm cheese. After  6 weeks, groups stopped their diets and put on wash out period for 3 weeks and later the  diets where switched between the them. Diet continued for another 6 weeks. Anthropometric measurements, dietary intakes, serum lipids and glucose levels were determined at the beginning and the end of each test period. Data were analyzed by Food Processor II and SPSS-13.    RESULTS: BMI, LDL_C, HDL_C, TG and serum Fructozamine were not significantly affected by dietary regimens. But Total cholesterol and fasting blood glucose decreased significantly in regimen containing lentil (P<0.05).    CONCLUSION: Consumption of cooked lentil as a LGI food in breakfast led to reduction of FBS and TC and improvement of glycemic control in type 2 diabetic patients.      Keywords: Diabetes Mellitus, Lentil, Lipid profiles, Blood glucose, Glycemic index, Clinical Trial.